Ground anchors



Nov. 15, 1955 c. w. PETERSEN GROUND ANCHORS Filed Sept. 7, 1951 ETL m m m a /A b United States Patent GROUND ANCHORS Clitrord W. Petersen, Wauwatosa, Wis., assignor to McGraw Electric Company, Milwaukee, Wis., a corporation of Delaware Application September 7, 1951, Serial No. 245,549 2 Claims. (Cl. 18992) This invention relates to a ground anchor for securing a stressed guy wire or cable into the ground.

An expanding ground anchor is a compact device which may be deposited at the bottom of a relatively small diameter cylindrical hole whereupon the flukes are pounded and forced at anangle into the undisturbed ground surrounding the hole. The greater the area of the ground anchor which can be forced into the ground beyond the diameter of the hole, the greater will be the holding power of the anchor to which the guy wire is attached.

One object of my invention is to provide an anchor in which the cutting and folding of the flukes results in the greatest amount of metal that can be expanded into undisturbed ground.

Another object of my invention is to provide a ground anchor having radially extending flukes which overlap when unexpanded and cause a rotational or screwing movement during expansion.

Other objects will appear from time to time in the course of the specification and claims.

An embodiment of my invention is shown in the accompanying drawings in which:

Fig. 1 illustrates the sheet metal blank cut so as to utilize the greatest amount of metal;

Fig. 2 is an elevation of the assembled ground anchor, unexpanded; and

Fig. 3 is a perspective view of the ground anchor, expanded.

Like reference characters designate like parts throughout the views.

Referring to Fig. 2, my ground anchor consists of an anchor rod 1 attached to a circular spreader plate 2 by means of a nut 3. A central aperture 6 is provided in the sheet metal plate 4 for freely receiving anchor rod 1 therethrough.

The anchor rod 1 has an attaching eye 7 at its upper end for fastening guy wires (not shown).

As can be seen in Fig. l, the flukes 9 are cut from an octagonally shaped piece of sheet metal 4 because the greatest amount of metal can be utilized from that shape, and it also provides points 8 at the tip of each fluke 9. The pointed tips 8 aid in cutting into the ground when the flukes are expanded. The sheet metal plate 4 is cut so as to have eight flukes 9 and the cutting of the individual flukes 9 bisects each side of the octagon as shown by the line 10. These cuts or slits 10 which form the flukes 9 are widened to form elongated slots 11 in order to facilitate overlapping. Each end of an elongated widened slot 11 nearest the center of hole 6 is in fact a point or apex which may be connected by an imaginary line to form a polygon defining a pounding surface 13. The lines 12 upon which flukes 9 are bent (shown in Fig. 1) are askew from the polygonal sides of surface 13.

The flukes 9 are bent at a slight angle on the line 12 so that when overlapped they will have a backward thrust which causes a rotational movement forward like a screw when a pounding device is thrust on 13 to expand the flukes. Each fluke 9 is also bent slightly along its length to form a crease 19 from the fold line 12 to the tip 8 for adding strength to the individual flukes. It is apparent that the configuration produced as aforesaid is an important aspect of the invention.

Fig. 2 illustrates the flukes 9 folded downward and slightly backward so as to overlap each other and form a compact unit. The tips of two opposing flukes 9 are fastened to the spreader plate 2 by the nut and screws 5 which are used to hold the assembly together during shipment or storage. Screws 5 may be removed prior to the expanding operation or sheared off during that operation.

The circular spreader plate 2 has a flat surface 14 at its center portion which serves as a stopping surface to notify the person pounding that the underside of the pounding surface 13 is resting on the spreader plate 2. From the fiat surface 14 the spreader plate tapers downward at 15 toward a depending annular margin 16 which serves to stiffen spreader plate 2. This tapered surface 15 guides the flukes 9 into the ground at a corresponding angle as shown in Fig. 3. Since the sheet metal plate 4 is not flattened out completely as in Fig. 1, there occurs a slight overlapping of the flukes. The overlap strengthens the flukes fonwithstanding bending load.

Welded to the underside of flat surface 14 on spreader plate 2 is a nut retainer strap 17 for providing additional metal support at the central portion of flat surface 14 and to which integral nut retaining skirts 18 are appended. If it is desired to abandon use of the anchor after it has been in the ground for an extended period, rod 1 may be simply driven downwardly beneath the ground line after removing the cable (not shown) from eye 7. Skirts 18 will readily diverge to permit nut 3 to pass deeper into the earth during this operation.

Any even number of fiukes 9 could be used without departing from the principle of my invention-as few as six or as many as fourteen. More than 14 flukes would reduce effectiveness of the anchor because the flukes 9 would be too narrow for adequate holding power. The flukes could also be cut from a circular shaped blank if desired.

My ground anchor has the following advantages:

The flukes are cut in such manner as to provide the greatest amount of earth gripping surface; the flukes are folded downward and at a slight angle backward overlapping each other so that when the pounding surface 13, integral with the flukes, is pounded by a driving device (not shown) the flukes rotate as they dig into the undisturbed ground; the flukes have points which facilitate cutting into the ground; and, a nut retainer strap and skirt welded to the underside of the base plate adds sufiicient strength to the latter for resisting deformation thereof under heavy loads.

The ground anchor is inserted into a hole which has a diameter similar to the diameter of the flukes in folded position as illustrated in Fig. 2. A driving tool (not shown) is seated on the pounding area 13 and then manually reciprocated vertically with considerable force against the pounding area. This drives the pounding surface downwardly until the underside touches the topside portion 14 of spreader plate 2. The meeting of these two surfaces 13 and 14 serves to indicate that the flukes are expanded.

As the pounding surface 13 moves downwardly the flukes 9 spread outwardly in coincidence with the tapered surface 15 of the spreader plate 2 so that the expanded flukes cut into the ground in substantially a horizontal plane but with a slight angle conforming to the bevel of surface 15. The flukes also slightly overlap each other so that as they cut into the undisturbed earth, a slight rotary motion takes place which gives the flukes an added dig into the ground and therefore gives greater strength and holding power to the ground anchor.

While one embodiment of the invention has been disclosed in detail, it is to be understood that the scope and spirit of the invention is to be limited only by the following claims.

I claim:

1. An expansible anchor comprising a circular spreader plate having a tapered upper surface, an anchor rod through said plate and secured thereto, a sheet metal member having a central aperture slidably receiving said rod and longitudinally spaced relative to said spreader plate, a polygonal pounding surface disposed about the central aperture of said sheet metal member, a plurality of flukes corresponding numerically to the sides of the polygon and defined by slits extending radially from the apices of said polygonal pounding surface, each of said flukes having a twisted bend adjacent and integral with said pounding surface on a line running from an apex of said polygon to a point radially displaced from the next adjacent apex along a slit, each fluke overlaying an adjacent fluke in substantially a truncated conical configuration about said spreader plate when unexpanded, whereby striking blows on said pounding surface will expand said fiukes in an arcuate path angularly relative to a plane coincident with the axis of said anchor rod by reacting against said spreader plate.

2. An expansible anchor comprising a circular spreader plate having a tapered upper surface, an anchor rod through said plate and secured thereto, a centrally apertured sheet metal member slidably receiving said rod and longitudinally spaced relative to said spreader plate, a polygonal pounding surface disposed about the central aperture of said sheet metal member, a plurality of flukes having equal length corresponding numerically to the sides of the polygon and defined by slits extending radially from the apices of said polygonal pounding surface, the end portions of each fluke having a point and a crease coincident with the axis of the fluke, each of said flukes having a twisted bend adjacent and integral with said pounding surface on a line running from an apex of said polygon to a point radially displaced from the next adjacent apex along a radial slit, each fluke overlaying an adjacent fluke in substantially truncated conical configuration about said spreader plate when unexpanded, whereby striking blows on said pounding surface will expand said fiukes in an arcuate path angularly relative to a plane coincident with the axis of said anchor rod by reacting against said spreader plate.

References Cited in the file of this patent UNITED STATES PATENTS 1,702,536 Cole Feb. 19, 1929 2,032,089 Handel Feb. 25, 1936 2,570,646 Cole Oct. 9, 1951 

